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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/dom/cache/Context.h"
#include "CacheCommon.h"
#include "mozilla/AutoRestore.h"
#include "mozilla/dom/SafeRefPtr.h"
#include "mozilla/dom/cache/Action.h"
#include "mozilla/dom/cache/FileUtils.h"
#include "mozilla/dom/cache/Manager.h"
#include "mozilla/dom/cache/ManagerId.h"
#include "mozilla/dom/quota/DirectoryLock.h"
#include "mozilla/dom/quota/QuotaManager.h"
#include "mozilla/dom/quota/ResultExtensions.h"
#include "mozIStorageConnection.h"
#include "nsIPrincipal.h"
#include "nsIRunnable.h"
#include "nsIThread.h"
#include "nsThreadUtils.h"
namespace {
using mozilla::dom::cache::Action;
using mozilla::dom::cache::CacheDirectoryMetadata;
class NullAction final : public Action {
public:
NullAction() = default;
virtual void RunOnTarget(mozilla::SafeRefPtr<Resolver> aResolver,
const mozilla::Maybe<CacheDirectoryMetadata>&,
Data*) override {
// Resolve success immediately. This Action does no actual work.
MOZ_DIAGNOSTIC_ASSERT(aResolver);
aResolver->Resolve(NS_OK);
}
};
} // namespace
namespace mozilla::dom::cache {
using mozilla::dom::quota::AssertIsOnIOThread;
using mozilla::dom::quota::DirectoryLock;
using mozilla::dom::quota::OpenDirectoryListener;
using mozilla::dom::quota::PERSISTENCE_TYPE_DEFAULT;
using mozilla::dom::quota::PersistenceType;
using mozilla::dom::quota::QuotaManager;
class Context::Data final : public Action::Data {
public:
explicit Data(nsISerialEventTarget* aTarget) : mTarget(aTarget) {
MOZ_DIAGNOSTIC_ASSERT(mTarget);
}
virtual mozIStorageConnection* GetConnection() const override {
MOZ_ASSERT(mTarget->IsOnCurrentThread());
return mConnection;
}
virtual void SetConnection(mozIStorageConnection* aConn) override {
MOZ_ASSERT(mTarget->IsOnCurrentThread());
MOZ_DIAGNOSTIC_ASSERT(!mConnection);
mConnection = aConn;
MOZ_DIAGNOSTIC_ASSERT(mConnection);
}
private:
~Data() {
// We could proxy release our data here, but instead just assert. The
// Context code should guarantee that we are destroyed on the target
// thread once the connection is initialized. If we're not, then
// QuotaManager might race and try to clear the origin out from under us.
MOZ_ASSERT_IF(mConnection, mTarget->IsOnCurrentThread());
}
nsCOMPtr<nsISerialEventTarget> mTarget;
nsCOMPtr<mozIStorageConnection> mConnection;
// Threadsafe counting because we're created on the PBackground thread
// and destroyed on the target IO thread.
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(Context::Data)
};
// Executed to perform the complicated dance of steps necessary to initialize
// the QuotaManager. This must be performed for each origin before any disk
// IO occurrs.
class Context::QuotaInitRunnable final : public nsIRunnable,
public OpenDirectoryListener {
public:
QuotaInitRunnable(SafeRefPtr<Context> aContext, SafeRefPtr<Manager> aManager,
Data* aData, nsISerialEventTarget* aTarget,
SafeRefPtr<Action> aInitAction)
: mContext(std::move(aContext)),
mThreadsafeHandle(mContext->CreateThreadsafeHandle()),
mManager(std::move(aManager)),
mData(aData),
mTarget(aTarget),
mInitAction(std::move(aInitAction)),
mInitiatingEventTarget(GetCurrentSerialEventTarget()),
mResult(NS_OK),
mState(STATE_INIT),
mCanceled(false) {
MOZ_DIAGNOSTIC_ASSERT(mContext);
MOZ_DIAGNOSTIC_ASSERT(mManager);
MOZ_DIAGNOSTIC_ASSERT(mData);
MOZ_DIAGNOSTIC_ASSERT(mTarget);
MOZ_DIAGNOSTIC_ASSERT(mInitiatingEventTarget);
MOZ_DIAGNOSTIC_ASSERT(mInitAction);
}
Maybe<DirectoryLock&> MaybeDirectoryLockRef() const {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
return ToMaybeRef(mDirectoryLock.get());
}
nsresult Dispatch() {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_INIT);
mState = STATE_GET_INFO;
nsresult rv = NS_DispatchToMainThread(this, nsIThread::DISPATCH_NORMAL);
if (NS_WARN_IF(NS_FAILED(rv))) {
mState = STATE_COMPLETE;
Clear();
}
return rv;
}
void Cancel() {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
MOZ_DIAGNOSTIC_ASSERT(!mCanceled);
mCanceled = true;
mInitAction->CancelOnInitiatingThread();
}
// OpenDirectoryListener methods
virtual void DirectoryLockAcquired(DirectoryLock* aLock) override;
virtual void DirectoryLockFailed() override;
private:
class SyncResolver final : public Action::Resolver {
public:
SyncResolver() : mResolved(false), mResult(NS_OK) {}
virtual void Resolve(nsresult aRv) override {
MOZ_DIAGNOSTIC_ASSERT(!mResolved);
mResolved = true;
mResult = aRv;
};
bool Resolved() const { return mResolved; }
nsresult Result() const { return mResult; }
private:
~SyncResolver() = default;
bool mResolved;
nsresult mResult;
NS_INLINE_DECL_REFCOUNTING(Context::QuotaInitRunnable::SyncResolver,
override)
};
~QuotaInitRunnable() {
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_COMPLETE);
MOZ_DIAGNOSTIC_ASSERT(!mContext);
MOZ_DIAGNOSTIC_ASSERT(!mInitAction);
}
enum State {
STATE_INIT,
STATE_GET_INFO,
STATE_CREATE_QUOTA_MANAGER,
STATE_WAIT_FOR_DIRECTORY_LOCK,
STATE_ENSURE_ORIGIN_INITIALIZED,
STATE_RUN_ON_TARGET,
STATE_RUNNING,
STATE_COMPLETING,
STATE_COMPLETE
};
void Complete(nsresult aResult) {
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_RUNNING || NS_FAILED(aResult));
MOZ_DIAGNOSTIC_ASSERT(NS_SUCCEEDED(mResult));
mResult = aResult;
mState = STATE_COMPLETING;
MOZ_ALWAYS_SUCCEEDS(
mInitiatingEventTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL));
}
void Clear() {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
MOZ_DIAGNOSTIC_ASSERT(mContext);
mContext = nullptr;
mManager = nullptr;
mInitAction = nullptr;
}
SafeRefPtr<Context> mContext;
SafeRefPtr<ThreadsafeHandle> mThreadsafeHandle;
SafeRefPtr<Manager> mManager;
RefPtr<Data> mData;
nsCOMPtr<nsISerialEventTarget> mTarget;
SafeRefPtr<Action> mInitAction;
nsCOMPtr<nsIEventTarget> mInitiatingEventTarget;
nsresult mResult;
Maybe<CacheDirectoryMetadata> mDirectoryMetadata;
RefPtr<DirectoryLock> mDirectoryLock;
State mState;
Atomic<bool> mCanceled;
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIRUNNABLE
};
void Context::QuotaInitRunnable::DirectoryLockAcquired(DirectoryLock* aLock) {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
MOZ_DIAGNOSTIC_ASSERT(aLock);
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_WAIT_FOR_DIRECTORY_LOCK);
MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock);
mDirectoryLock = aLock;
MOZ_DIAGNOSTIC_ASSERT(mDirectoryLock->Id() >= 0);
mDirectoryMetadata->mDirectoryLockId = mDirectoryLock->Id();
if (mCanceled) {
Complete(NS_ERROR_ABORT);
return;
}
QuotaManager* qm = QuotaManager::Get();
MOZ_DIAGNOSTIC_ASSERT(qm);
mState = STATE_ENSURE_ORIGIN_INITIALIZED;
nsresult rv = qm->IOThread()->Dispatch(this, nsIThread::DISPATCH_NORMAL);
if (NS_WARN_IF(NS_FAILED(rv))) {
Complete(rv);
return;
}
}
void Context::QuotaInitRunnable::DirectoryLockFailed() {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_WAIT_FOR_DIRECTORY_LOCK);
MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock);
NS_WARNING("Failed to acquire a directory lock!");
Complete(NS_ERROR_FAILURE);
}
NS_IMPL_ISUPPORTS(mozilla::dom::cache::Context::QuotaInitRunnable, nsIRunnable);
// The QuotaManager init state machine is represented in the following diagram:
//
// +---------------+
// | Start | Resolve(error)
// | (Orig Thread) +---------------------+
// +-------+-------+ |
// | |
// +----------v-----------+ |
// | GetInfo | Resolve(error) |
// | (Main Thread) +-----------------+
// +----------+-----------+ |
// | |
// +----------v-----------+ |
// | CreateQuotaManager | Resolve(error) |
// | (Orig Thread) +-----------------+
// +----------+-----------+ |
// | |
// +----------v-----------+ |
// | WaitForDirectoryLock | Resolve(error) |
// | (Orig Thread) +-----------------+
// +----------+-----------+ |
// | |
// +----------v------------+ |
// |EnsureOriginInitialized| Resolve(error) |
// | (Quota IO Thread) +----------------+
// +----------+------------+ |
// | |
// +----------v------------+ |
// | RunOnTarget | Resolve(error) |
// | (Target Thread) +----------------+
// +----------+------------+ |
// | |
// +---------v---------+ +------v------+
// | Running | | Completing |
// | (Target Thread) +------------>(Orig Thread)|
// +-------------------+ +------+------+
// |
// +-----v----+
// | Complete |
// +----------+
//
// The initialization process proceeds through the main states. If an error
// occurs, then we transition to Completing state back on the original thread.
NS_IMETHODIMP
Context::QuotaInitRunnable::Run() {
// May run on different threads depending on the state. See individual
// state cases for thread assertions.
SafeRefPtr<SyncResolver> resolver = MakeSafeRefPtr<SyncResolver>();
switch (mState) {
// -----------------------------------
case STATE_GET_INFO: {
MOZ_ASSERT(NS_IsMainThread());
auto res = [this]() -> Result<Ok, nsresult> {
if (mCanceled) {
return Err(NS_ERROR_ABORT);
}
nsCOMPtr<nsIPrincipal> principal = mManager->GetManagerId().Principal();
QM_TRY_UNWRAP(auto principalMetadata,
QuotaManager::GetInfoFromPrincipal(principal));
mDirectoryMetadata.emplace(std::move(principalMetadata));
mState = STATE_CREATE_QUOTA_MANAGER;
MOZ_ALWAYS_SUCCEEDS(
mInitiatingEventTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL));
return Ok{};
}();
if (res.isErr()) {
resolver->Resolve(res.inspectErr());
}
break;
}
// ----------------------------------
case STATE_CREATE_QUOTA_MANAGER: {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
if (mCanceled || QuotaManager::IsShuttingDown()) {
resolver->Resolve(NS_ERROR_ABORT);
break;
}
QM_TRY(QuotaManager::EnsureCreated(), QM_PROPAGATE,
[&resolver](const auto rv) { resolver->Resolve(rv); });
MOZ_DIAGNOSTIC_ASSERT(QuotaManager::Get());
// Open directory
RefPtr<DirectoryLock> directoryLock =
QuotaManager::Get()->CreateDirectoryLock(PERSISTENCE_TYPE_DEFAULT,
*mDirectoryMetadata,
quota::Client::DOMCACHE,
/* aExclusive */ false);
// DirectoryLock::Acquire() will hold a reference to us as a listener. We
// will then get DirectoryLockAcquired() on the owning thread when it is
// safe to access our storage directory.
mState = STATE_WAIT_FOR_DIRECTORY_LOCK;
directoryLock->Acquire(this);
break;
}
// ----------------------------------
case STATE_ENSURE_ORIGIN_INITIALIZED: {
AssertIsOnIOThread();
auto res = [this]() -> Result<Ok, nsresult> {
if (mCanceled) {
return Err(NS_ERROR_ABORT);
}
QuotaManager* quotaManager = QuotaManager::Get();
MOZ_DIAGNOSTIC_ASSERT(quotaManager);
QM_TRY(MOZ_TO_RESULT(quotaManager->EnsureStorageIsInitialized()));
QM_TRY(
MOZ_TO_RESULT(quotaManager->EnsureTemporaryStorageIsInitialized()));
QM_TRY_UNWRAP(mDirectoryMetadata->mDir,
quotaManager
->EnsureTemporaryOriginIsInitialized(
PERSISTENCE_TYPE_DEFAULT, *mDirectoryMetadata)
.map([](const auto& res) { return res.first; }));
mState = STATE_RUN_ON_TARGET;
MOZ_ALWAYS_SUCCEEDS(
mTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL));
return Ok{};
}();
if (res.isErr()) {
resolver->Resolve(res.inspectErr());
}
break;
}
// -------------------
case STATE_RUN_ON_TARGET: {
MOZ_ASSERT(mTarget->IsOnCurrentThread());
mState = STATE_RUNNING;
// Execute the provided initialization Action. The Action must Resolve()
// before returning.
mInitAction->RunOnTarget(resolver.clonePtr(), mDirectoryMetadata, mData);
MOZ_DIAGNOSTIC_ASSERT(resolver->Resolved());
mData = nullptr;
// If the database was opened, then we should always succeed when creating
// the marker file. If it wasn't opened successfully, then no need to
// create a marker file anyway.
if (NS_SUCCEEDED(resolver->Result())) {
MOZ_ALWAYS_SUCCEEDS(CreateMarkerFile(*mDirectoryMetadata));
}
break;
}
// -------------------
case STATE_COMPLETING: {
NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable);
mInitAction->CompleteOnInitiatingThread(mResult);
mContext->OnQuotaInit(mResult, mDirectoryMetadata,
mDirectoryLock.forget());
mState = STATE_COMPLETE;
// Explicitly cleanup here as the destructor could fire on any of
// the threads we have bounced through.
Clear();
break;
}
// -----
case STATE_WAIT_FOR_DIRECTORY_LOCK:
default: {
MOZ_CRASH("unexpected state in QuotaInitRunnable");
}
}
if (resolver->Resolved()) {
Complete(resolver->Result());
}
return NS_OK;
}
// Runnable wrapper around Action objects dispatched on the Context. This
// runnable executes the Action on the appropriate threads while the Context
// is initialized.
class Context::ActionRunnable final : public nsIRunnable,
public Action::Resolver,
public Context::Activity {
public:
ActionRunnable(SafeRefPtr<Context> aContext, Data* aData,
nsISerialEventTarget* aTarget, SafeRefPtr<Action> aAction,
const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata)
: mContext(std::move(aContext)),
mData(aData),
mTarget(aTarget),
mAction(std::move(aAction)),
mDirectoryMetadata(aDirectoryMetadata),
mInitiatingThread(GetCurrentEventTarget()),
mState(STATE_INIT),
mResult(NS_OK),
mExecutingRunOnTarget(false) {
MOZ_DIAGNOSTIC_ASSERT(mContext);
// mData may be nullptr
MOZ_DIAGNOSTIC_ASSERT(mTarget);
MOZ_DIAGNOSTIC_ASSERT(mAction);
// mDirectoryMetadata.mDir may be nullptr if QuotaInitRunnable failed
MOZ_DIAGNOSTIC_ASSERT(mInitiatingThread);
}
nsresult Dispatch() {
NS_ASSERT_OWNINGTHREAD(ActionRunnable);
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_INIT);
mState = STATE_RUN_ON_TARGET;
nsresult rv = mTarget->Dispatch(this, nsIEventTarget::DISPATCH_NORMAL);
if (NS_WARN_IF(NS_FAILED(rv))) {
mState = STATE_COMPLETE;
Clear();
}
return rv;
}
virtual bool MatchesCacheId(CacheId aCacheId) const override {
NS_ASSERT_OWNINGTHREAD(ActionRunnable);
return mAction->MatchesCacheId(aCacheId);
}
virtual void Cancel() override {
NS_ASSERT_OWNINGTHREAD(ActionRunnable);
mAction->CancelOnInitiatingThread();
}
virtual void Resolve(nsresult aRv) override {
MOZ_ASSERT(mTarget->IsOnCurrentThread());
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_RUNNING);
mResult = aRv;
// We ultimately must complete on the initiating thread, but bounce through
// the current thread again to ensure that we don't destroy objects and
// state out from under the currently running action's stack.
mState = STATE_RESOLVING;
// If we were resolved synchronously within Action::RunOnTarget() then we
// can avoid a thread bounce and just resolve once RunOnTarget() returns.
// The Run() method will handle this by looking at mState after
// RunOnTarget() returns.
if (mExecutingRunOnTarget) {
return;
}
// Otherwise we are in an asynchronous resolve. And must perform a thread
// bounce to run on the target thread again.
MOZ_ALWAYS_SUCCEEDS(mTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL));
}
private:
~ActionRunnable() {
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_COMPLETE);
MOZ_DIAGNOSTIC_ASSERT(!mContext);
MOZ_DIAGNOSTIC_ASSERT(!mAction);
}
void Clear() {
NS_ASSERT_OWNINGTHREAD(ActionRunnable);
MOZ_DIAGNOSTIC_ASSERT(mContext);
MOZ_DIAGNOSTIC_ASSERT(mAction);
mContext->RemoveActivity(*this);
mContext = nullptr;
mAction = nullptr;
}
enum State {
STATE_INIT,
STATE_RUN_ON_TARGET,
STATE_RUNNING,
STATE_RESOLVING,
STATE_COMPLETING,
STATE_COMPLETE
};
SafeRefPtr<Context> mContext;
RefPtr<Data> mData;
nsCOMPtr<nsISerialEventTarget> mTarget;
SafeRefPtr<Action> mAction;
const Maybe<CacheDirectoryMetadata> mDirectoryMetadata;
nsCOMPtr<nsIEventTarget> mInitiatingThread;
State mState;
nsresult mResult;
// Only accessible on target thread;
bool mExecutingRunOnTarget;
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIRUNNABLE
};
NS_IMPL_ISUPPORTS(mozilla::dom::cache::Context::ActionRunnable, nsIRunnable);
// The ActionRunnable has a simpler state machine. It basically needs to run
// the action on the target thread and then complete on the original thread.
//
// +-------------+
// | Start |
// |(Orig Thread)|
// +-----+-------+
// |
// +-------v---------+
// | RunOnTarget |
// |Target IO Thread)+---+ Resolve()
// +-------+---------+ |
// | |
// +-------v----------+ |
// | Running | |
// |(Target IO Thread)| |
// +------------------+ |
// | Resolve() |
// +-------v----------+ |
// | Resolving <--+ +-------------+
// | | | Completing |
// |(Target IO Thread)+---------------------->(Orig Thread)|
// +------------------+ +-------+-----+
// |
// |
// +----v---+
// |Complete|
// +--------+
//
// Its important to note that synchronous actions will effectively Resolve()
// out of the Running state immediately. Asynchronous Actions may remain
// in the Running state for some time, but normally the ActionRunnable itself
// does not see any execution there. Its all handled internal to the Action.
NS_IMETHODIMP
Context::ActionRunnable::Run() {
switch (mState) {
// ----------------------
case STATE_RUN_ON_TARGET: {
MOZ_ASSERT(mTarget->IsOnCurrentThread());
MOZ_DIAGNOSTIC_ASSERT(!mExecutingRunOnTarget);
// Note that we are calling RunOnTarget(). This lets us detect
// if Resolve() is called synchronously.
AutoRestore<bool> executingRunOnTarget(mExecutingRunOnTarget);
mExecutingRunOnTarget = true;
mState = STATE_RUNNING;
mAction->RunOnTarget(SafeRefPtrFromThis(), mDirectoryMetadata, mData);
mData = nullptr;
// Resolve was called synchronously from RunOnTarget(). We can
// immediately move to completing now since we are sure RunOnTarget()
// completed.
if (mState == STATE_RESOLVING) {
// Use recursion instead of switch case fall-through... Seems slightly
// easier to understand.
Run();
}
break;
}
// -----------------
case STATE_RESOLVING: {
MOZ_ASSERT(mTarget->IsOnCurrentThread());
// The call to Action::RunOnTarget() must have returned now if we
// are running on the target thread again. We may now proceed
// with completion.
mState = STATE_COMPLETING;
// Shutdown must be delayed until all Contexts are destroyed. Crash
// for this invariant violation.
MOZ_ALWAYS_SUCCEEDS(
mInitiatingThread->Dispatch(this, nsIThread::DISPATCH_NORMAL));
break;
}
// -------------------
case STATE_COMPLETING: {
NS_ASSERT_OWNINGTHREAD(ActionRunnable);
mAction->CompleteOnInitiatingThread(mResult);
mState = STATE_COMPLETE;
// Explicitly cleanup here as the destructor could fire on any of
// the threads we have bounced through.
Clear();
break;
}
// -----------------
default: {
MOZ_CRASH("unexpected state in ActionRunnable");
break;
}
}
return NS_OK;
}
void Context::ThreadsafeHandle::AllowToClose() {
if (mOwningEventTarget->IsOnCurrentThread()) {
AllowToCloseOnOwningThread();
return;
}
// Dispatch is guaranteed to succeed here because we block shutdown until
// all Contexts have been destroyed.
nsCOMPtr<nsIRunnable> runnable = NewRunnableMethod(
"dom::cache::Context::ThreadsafeHandle::AllowToCloseOnOwningThread", this,
&ThreadsafeHandle::AllowToCloseOnOwningThread);
MOZ_ALWAYS_SUCCEEDS(mOwningEventTarget->Dispatch(runnable.forget(),
nsIThread::DISPATCH_NORMAL));
}
void Context::ThreadsafeHandle::InvalidateAndAllowToClose() {
if (mOwningEventTarget->IsOnCurrentThread()) {
InvalidateAndAllowToCloseOnOwningThread();
return;
}
// Dispatch is guaranteed to succeed here because we block shutdown until
// all Contexts have been destroyed.
nsCOMPtr<nsIRunnable> runnable = NewRunnableMethod(
"dom::cache::Context::ThreadsafeHandle::"
"InvalidateAndAllowToCloseOnOwningThread",
this, &ThreadsafeHandle::InvalidateAndAllowToCloseOnOwningThread);
MOZ_ALWAYS_SUCCEEDS(mOwningEventTarget->Dispatch(runnable.forget(),
nsIThread::DISPATCH_NORMAL));
}
Context::ThreadsafeHandle::ThreadsafeHandle(SafeRefPtr<Context> aContext)
: mStrongRef(std::move(aContext)),
mWeakRef(mStrongRef.unsafeGetRawPtr()),
mOwningEventTarget(GetCurrentSerialEventTarget()) {}
Context::ThreadsafeHandle::~ThreadsafeHandle() {
// Normally we only touch mStrongRef on the owning thread. This is safe,
// however, because when we do use mStrongRef on the owning thread we are
// always holding a strong ref to the ThreadsafeHandle via the owning
// runnable. So we cannot run the ThreadsafeHandle destructor simultaneously.
if (!mStrongRef || mOwningEventTarget->IsOnCurrentThread()) {
return;
}
// Dispatch in NS_ProxyRelease is guaranteed to succeed here because we block
// shutdown until all Contexts have been destroyed. Therefore it is ok to have
// MOZ_ALWAYS_SUCCEED here.
MOZ_ALWAYS_SUCCEEDS(NS_ProxyRelease("Context::ThreadsafeHandle::mStrongRef",
mOwningEventTarget, mStrongRef.forget()));
}
void Context::ThreadsafeHandle::AllowToCloseOnOwningThread() {
MOZ_ASSERT(mOwningEventTarget->IsOnCurrentThread());
// A Context "closes" when its ref count drops to zero. Dropping this
// strong ref is necessary, but not sufficient for the close to occur.
// Any outstanding IO will continue and keep the Context alive. Once
// the Context is idle, it will be destroyed.
// First, tell the context to flush any target thread shared data. This
// data must be released on the target thread prior to running the Context
// destructor. This will schedule an Action which ensures that the
// ~Context() is not immediately executed when we drop the strong ref.
if (mStrongRef) {
mStrongRef->DoomTargetData();
}
// Now drop our strong ref and let Context finish running any outstanding
// Actions.
mStrongRef = nullptr;
}
void Context::ThreadsafeHandle::InvalidateAndAllowToCloseOnOwningThread() {
MOZ_ASSERT(mOwningEventTarget->IsOnCurrentThread());
// Cancel the Context through the weak reference. This means we can
// allow the Context to close by dropping the strong ref, but then
// still cancel ongoing IO if necessary.
if (mWeakRef) {
mWeakRef->Invalidate();
}
// We should synchronously have AllowToCloseOnOwningThread called when
// the Context is canceled.
MOZ_DIAGNOSTIC_ASSERT(!mStrongRef);
}
void Context::ThreadsafeHandle::ContextDestroyed(Context& aContext) {
MOZ_ASSERT(mOwningEventTarget->IsOnCurrentThread());
MOZ_DIAGNOSTIC_ASSERT(!mStrongRef);
MOZ_DIAGNOSTIC_ASSERT(mWeakRef);
MOZ_DIAGNOSTIC_ASSERT(mWeakRef == &aContext);
mWeakRef = nullptr;
}
// static
SafeRefPtr<Context> Context::Create(SafeRefPtr<Manager> aManager,
nsISerialEventTarget* aTarget,
SafeRefPtr<Action> aInitAction,
Maybe<Context&> aOldContext) {
auto context = MakeSafeRefPtr<Context>(std::move(aManager), aTarget,
std::move(aInitAction));
context->Init(aOldContext);
return context;
}
Context::Context(SafeRefPtr<Manager> aManager, nsISerialEventTarget* aTarget,
SafeRefPtr<Action> aInitAction)
: mManager(std::move(aManager)),
mTarget(aTarget),
mData(new Data(aTarget)),
mState(STATE_CONTEXT_PREINIT),
mOrphanedData(false),
mInitAction(std::move(aInitAction)) {
MOZ_DIAGNOSTIC_ASSERT(mManager);
MOZ_DIAGNOSTIC_ASSERT(mTarget);
}
void Context::Dispatch(SafeRefPtr<Action> aAction) {
NS_ASSERT_OWNINGTHREAD(Context);
MOZ_DIAGNOSTIC_ASSERT(aAction);
MOZ_DIAGNOSTIC_ASSERT(mState != STATE_CONTEXT_CANCELED);
if (mState == STATE_CONTEXT_CANCELED) {
return;
}
if (mState == STATE_CONTEXT_INIT || mState == STATE_CONTEXT_PREINIT) {
PendingAction* pending = mPendingActions.AppendElement();
pending->mAction = std::move(aAction);
return;
}
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_CONTEXT_READY);
DispatchAction(std::move(aAction));
}
Maybe<DirectoryLock&> Context::MaybeDirectoryLockRef() const {
NS_ASSERT_OWNINGTHREAD(Context);
if (mState == STATE_CONTEXT_PREINIT) {
MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable);
MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock);
return Nothing();
}
if (mState == STATE_CONTEXT_INIT) {
MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock);
return mInitRunnable->MaybeDirectoryLockRef();
}
return ToMaybeRef(mDirectoryLock.get());
}
void Context::CancelAll() {
NS_ASSERT_OWNINGTHREAD(Context);
// In PREINIT state we have not dispatch the init action yet. Just
// forget it.
if (mState == STATE_CONTEXT_PREINIT) {
MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable);
mInitAction = nullptr;
// In INIT state we have dispatched the runnable, but not received the
// async completion yet. Cancel the runnable, but don't forget about it
// until we get OnQuotaInit() callback.
} else if (mState == STATE_CONTEXT_INIT) {
mInitRunnable->Cancel();
}
mState = STATE_CONTEXT_CANCELED;
mPendingActions.Clear();
for (const auto& activity : mActivityList.ForwardRange()) {
activity->Cancel();
}
AllowToClose();
}
bool Context::IsCanceled() const {
NS_ASSERT_OWNINGTHREAD(Context);
return mState == STATE_CONTEXT_CANCELED;
}
void Context::Invalidate() {
NS_ASSERT_OWNINGTHREAD(Context);
mManager->NoteClosing();
CancelAll();
}
void Context::AllowToClose() {
NS_ASSERT_OWNINGTHREAD(Context);
if (mThreadsafeHandle) {
mThreadsafeHandle->AllowToClose();
}
}
void Context::CancelForCacheId(CacheId aCacheId) {
NS_ASSERT_OWNINGTHREAD(Context);
// Remove matching pending actions
mPendingActions.RemoveElementsBy([aCacheId](const auto& pendingAction) {
return pendingAction.mAction->MatchesCacheId(aCacheId);
});
// Cancel activities and let them remove themselves
for (const auto& activity : mActivityList.ForwardRange()) {
if (activity->MatchesCacheId(aCacheId)) {
activity->Cancel();
}
}
}
Context::~Context() {
NS_ASSERT_OWNINGTHREAD(Context);
MOZ_DIAGNOSTIC_ASSERT(mManager);
MOZ_DIAGNOSTIC_ASSERT(!mData);
if (mThreadsafeHandle) {
mThreadsafeHandle->ContextDestroyed(*this);
}
// Note, this may set the mOrphanedData flag.
mManager->RemoveContext(*this);
if (mDirectoryMetadata && mDirectoryMetadata->mDir && !mOrphanedData) {
MOZ_ALWAYS_SUCCEEDS(DeleteMarkerFile(*mDirectoryMetadata));
}
if (mNextContext) {
mNextContext->Start();
}
}
void Context::Init(Maybe<Context&> aOldContext) {
NS_ASSERT_OWNINGTHREAD(Context);
if (aOldContext) {
aOldContext->SetNextContext(SafeRefPtrFromThis());
return;
}
Start();
}
void Context::Start() {
NS_ASSERT_OWNINGTHREAD(Context);
// Previous context closing delayed our start, but then we were canceled.
// In this case, just do nothing here.
if (mState == STATE_CONTEXT_CANCELED) {
MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable);
MOZ_DIAGNOSTIC_ASSERT(!mInitAction);
// If we can't initialize the quota subsystem we will never be able to
// clear our shared data object via the target IO thread. Instead just
// clear it here to maintain the invariant that the shared data is
// cleared before Context destruction.
mData = nullptr;
return;
}
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_CONTEXT_PREINIT);
MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable);
mInitRunnable =
new QuotaInitRunnable(SafeRefPtrFromThis(), mManager.clonePtr(), mData,
mTarget, std::move(mInitAction));
mState = STATE_CONTEXT_INIT;
nsresult rv = mInitRunnable->Dispatch();
if (NS_FAILED(rv)) {
// Shutdown must be delayed until all Contexts are destroyed. Shutdown
// must also prevent any new Contexts from being constructed. Crash
// for this invariant violation.
MOZ_CRASH("Failed to dispatch QuotaInitRunnable.");
}
}
void Context::DispatchAction(SafeRefPtr<Action> aAction, bool aDoomData) {
NS_ASSERT_OWNINGTHREAD(Context);
auto runnable =
MakeSafeRefPtr<ActionRunnable>(SafeRefPtrFromThis(), mData, mTarget,
std::move(aAction), mDirectoryMetadata);
if (aDoomData) {
mData = nullptr;
}
nsresult rv = runnable->Dispatch();
if (NS_FAILED(rv)) {
// Shutdown must be delayed until all Contexts are destroyed. Crash
// for this invariant violation.
MOZ_CRASH("Failed to dispatch ActionRunnable to target thread.");
}
AddActivity(*runnable);
}
void Context::OnQuotaInit(
nsresult aRv, const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata,
already_AddRefed<DirectoryLock> aDirectoryLock) {
NS_ASSERT_OWNINGTHREAD(Context);
MOZ_DIAGNOSTIC_ASSERT(mInitRunnable);
mInitRunnable = nullptr;
if (aDirectoryMetadata) {
mDirectoryMetadata.emplace(*aDirectoryMetadata);
}
// Always save the directory lock to ensure QuotaManager does not shutdown
// before the Context has gone away.
MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock);
mDirectoryLock = aDirectoryLock;
// If we opening the context failed, but we were not explicitly canceled,
// still treat the entire context as canceled. We don't want to allow
// new actions to be dispatched. We also cannot leave the context in
// the INIT state after failing to open.
if (NS_FAILED(aRv)) {
mState = STATE_CONTEXT_CANCELED;
}
if (mState == STATE_CONTEXT_CANCELED) {
for (uint32_t i = 0; i < mPendingActions.Length(); ++i) {
mPendingActions[i].mAction->CompleteOnInitiatingThread(aRv);
}
mPendingActions.Clear();
mThreadsafeHandle->AllowToClose();
// Context will destruct after return here and last ref is released.
return;
}
MOZ_DIAGNOSTIC_ASSERT(mState == STATE_CONTEXT_INIT);
mState = STATE_CONTEXT_READY;
for (uint32_t i = 0; i < mPendingActions.Length(); ++i) {
DispatchAction(std::move(mPendingActions[i].mAction));
}
mPendingActions.Clear();
}
void Context::AddActivity(Activity& aActivity) {
NS_ASSERT_OWNINGTHREAD(Context);
MOZ_ASSERT(!mActivityList.Contains(&aActivity));
mActivityList.AppendElement(WrapNotNullUnchecked(&aActivity));
}
void Context::RemoveActivity(Activity& aActivity) {
NS_ASSERT_OWNINGTHREAD(Context);
MOZ_ALWAYS_TRUE(mActivityList.RemoveElement(&aActivity));
MOZ_ASSERT(!mActivityList.Contains(&aActivity));
}
void Context::NoteOrphanedData() {
NS_ASSERT_OWNINGTHREAD(Context);
// This may be called more than once
mOrphanedData = true;
}
SafeRefPtr<Context::ThreadsafeHandle> Context::CreateThreadsafeHandle() {
NS_ASSERT_OWNINGTHREAD(Context);
if (!mThreadsafeHandle) {
mThreadsafeHandle = MakeSafeRefPtr<ThreadsafeHandle>(SafeRefPtrFromThis());
}
return mThreadsafeHandle.clonePtr();
}
void Context::SetNextContext(SafeRefPtr<Context> aNextContext) {
NS_ASSERT_OWNINGTHREAD(Context);
MOZ_DIAGNOSTIC_ASSERT(aNextContext);
MOZ_DIAGNOSTIC_ASSERT(!mNextContext);
mNextContext = std::move(aNextContext);
}
void Context::DoomTargetData() {
NS_ASSERT_OWNINGTHREAD(Context);
MOZ_DIAGNOSTIC_ASSERT(mData);
// We are about to drop our reference to the Data. We need to ensure that
// the ~Context() destructor does not run until contents of Data have been
// released on the Target thread.
// Dispatch a no-op Action. This will hold the Context alive through a
// roundtrip to the target thread and back to the owning thread. The
// ref to the Data object is cleared on the owning thread after creating
// the ActionRunnable, but before dispatching it.
DispatchAction(MakeSafeRefPtr<NullAction>(), true /* doomed data */);
MOZ_DIAGNOSTIC_ASSERT(!mData);
}
} // namespace mozilla::dom::cache